This disclosure relates generally to systems suitable for early production in deep water applications. In some examples, this disclosure relates to systems suitable for early production in high pressure and/or high temperature environments. In some examples, this disclosure relates to systems suitable for early production that permit handling production of gas.
Early production systems may be needed to evaluate a hydrocarbon reservoir accessed by a wellbore recently drilled to the reservoir. To evaluate the reservoir, the reservoir is often produced for a short period of time (e.g., to perform a draw down and shut-off test or other well tests). Because reservoir evaluation is short (compared to the period of production of the reservoir), a dynamic positioning (“DP”) system, rather than a full mooring system, is often used to maintain a hydrocarbon processing facility on the sea surface above a wellhead terminating the wellbore at the sea bed. For example, a Mobile Offshore Drilling Unit (“MODU”) or a drill ship connect to the wellhead may be used process the hydrocarbon fluid produced by the reservoir. A tanker vessel can in turn be connected to the MODU and can move relative to the MODU. The tanker vessel stores the hydrocarbon produced. When using a DP system, it is required to be able to disconnect from the wellhead on very short notice (emergency disconnect). It is also advantageous to have a single point of connection.
The MODU may be connected to the wellhead via a vertical tree and a riser. This technology has been used in a number of prior applications, such as completion and workovers. For early production however, more than a single seafloor connection may be required. Also, advanced functionality—such as a High-Integrity Pressure Protection System (“HIPPS”) or other additional safety systems, may often be needed. Thus, there is a continuing need in the art for methods and apparatus for providing early production systems that may be used in high pressure and/or high temperature environments (“HPHT environments”). The early production systems may optionally permit handling production of gas dissolved in the reservoir hydrocarbon.